[G1 Q&A, Help & Troubleshooting] MV10:
This is a long thread because I'm trying to provide the maximum detail possible in the hopes of luring some experts to assist. I am a developer with 30+ years experience, though with little *nix experience, since I hitched my wagon to WinTel when people stopped hiring assembly programmers and the term "GUI" began appearing in help wanted ads.

Yesterday, based upon my experience with one phone that I successfully upgraded to CM6-RC1 and another one that failed, I posted a new thread in the G1 General section, which was probably the wrong place for it. Both phones are US TMo G1's purchased within a few days of each other, around December 2009.

During the subsequent 12 hours I read everything I could find about the dreaded "E: Can't find MISC: / (No space left on device)" problem, which I eventually determined was preventing me from proceeding further.

I found many, many examples of people on all types of hardware who were (and many still are) stuck with a hosed-up misc with no idea how to proceed. This was somewhat alarming to me.

I found a few people who were apparently able to fix it by simply doing a flash_image of a misc.img copied from elsewhere. I found a few who seemed to have fixed it with dd. I found others who went through various combinations of installing other things until the problem mysteriously vanished. I found great info about what the misc partition is and how it's used.

What I did not find is:

(a) any clear explanation of how it gets hosed in the first place,

(b) any clear explanation of how to troubleshoot it,

and most importantly (c) any clear explanation of ways to fix it.

This thread is a request for an expert to step in and fill those gaps. Maybe if we can get some "misc lore" in a single place, other people who encounter the problem won't be left hanging.

So first the back story:

Two days ago I decided to install CM6-RC1 on my own G1. It went very smoothly. I was already on Cupcake, so I formatted the card, downgraded back to RC29, I installed Cupcake, formatted again from the phone, used flashrec to install RA 1.7 (which is amazing, by the way; I may be a n00b to phone-guts but that is already apparent), verified the radio version, installed DangerSPL, installed CM6-RC1, and installed the Google Apps. Flawless process.

Loved it. CM6 is great. So the next morning I had my wife leave her phone at home with me. I had seen a thread which led me to believe that the card didn't necessarily have to be formatted twice. I was under the impression I could format it once and drop all the files out there -- only Cupcake needed to be named update.zip for the process outlined above.

So I connected her phone to my laptop, reformatted to FAT32 over USB from Win7, copied all 211 MB of files over, disconnected and went into flashboot. The RC29 downgrade worked fine. I restarted and logged in just to be sure RC29 was on there. I powered off and restarted in recovery mode -- and the misc problem was already there.

In the stock /!\ recovery screen, ALT+L showed the misc error. I couldn't remember if I had seen that previously (having only done this once before), so I hit ALT+S and hoped for the best. The progress bar went about halfway then bombed on an assert in line 4. And that's as far as I got updating my wife's phone: in theory my story could stop here, but being a lifelong geek-type, I decided to forge ahead. I didn't yet know the importance of misc or even recognize it as my main problem, so bear with me.

I rebooted and rooted via telnet and used flashrec to install RA, and tried installing Cupcake that way. I get a different error from RA: No signature, verification failed. I thought I might have a bad file, somehow, despite having used the same update.zip that went into my G1 just fine, so I downloaded it again from megaupload. Then I downloaded the other one named signed-kila-ota. Then I did a file compare and confirmed they're identical. That won't load through RA. Not sure what's up with that.

But after thinking about it and doing more reading, I concluded I probably didn't need Cupcake for CM6-RC1, I just needed the correct radio image to support DangerSPL. So I grabbed the G1 2.22.23 radio image and tried installing that through RA. It extracts and installs ok, then dumps the Can't read Misc error, then tells me to reboot to complete. So I reboot -- and it goes back into the running OS, of course. And then the light goes on, since I did clearly remember on my own G1 it went back into RA, not into Android.

More digging uncovers the radio/SPL thread that explains how misc is used to control reboots, and I finally clearly realize that misc is my problem. (Actually I still don't know why Cupcake won't load from RA, but I still suspect if I can just load the right radio image, it shouldn't matter.)

During the following six hours I have tried a huge variety of things to fix misc, primarily working through an adb connection.

First I tried making a nandroid backup from my working G1. Took me awhile to figure out I had to do it from the command line to force it to backup misc, then I wasted time trying to get the command line to restore that backup, then I finally made another backup on the non-working G1 and copied the "good" misc over -- and still couldn't get it to restore (kept telling me something about being the current version, which I interpreted to mean it wasn't restoring because it thought the backup already matched the live filesystem).

Again, not knowing much about *nix, at this point I was convinced misc was simply dead and gone. I know what a disk partition is, but I didn't see misc (or the others like recovery) in parted, so I don't think I even understand what it means to say misc is a partition. But I didn't see it anywhere, so I thought it had been erased or overwritten or something along those lines.

Then I ran across a thread in which someone suggested doing a "cat /proc/mtd" which yielded the following:

dev: size erasesize name
mtd0: 00040000 00020000 "misc"
mtd1: 00500000 00020000 "recovery"
mtd2: 00280000 00020000 "boot"
mtd3: 04380000 00020000 "system"
mtd4: 04380000 00020000 "cache"
mtd5: 04ac0000 00020000 "userdata"

I don't know what it means, but at least I see the system still knows something about misc.

Someone else asked for "dump_image misc /dev/zero" for diagnostic purposes, which yields:

mtd: ECC errors (0 soft, 1 hard) at 0x00000000
mtd: ECC errors (0 soft, 1 hard) at 0x00020000

Someone suggested "cat /dev/zero > /dev/mtd/mtd0" which results in the error message "cat: write error: No space left on device".

I tried copying misc.img out of the backup folder to the sdcard root and doing "flash_image misc /sdcard/misc.img" and was rewarded with the following lines which I can't interpret, although they're clearly related to the output shown above (I assume flash_image is probably a script or something, which is just doing those same steps internally?):

mtd: ECC errors (0 soft, 1 hard) at 0x00000000
mtd: ECC errors (0 soft, 1 hard) at 0x00020000
mtd: erase failure at 0x00000000 (I/O error)
mtd: erase failure at 0x00000000 (I/O error)
mtd: skipping write block at 0x00000000
error writing misc: No space left on device

I ran across another thread which suggested the command "dd if=/sdcard/misc.img of=/dev/block/mtd0"... that produced this initially encouraging-looking output, though I don't know what it means and it didn't fix misc:

512+0 records in
512+0 records out

I also saw a few steps and suggestions relating to fastboot. I didn't try any of these since the only instructions I could find for setting up fastboot (in that stickied noob thread) requires a version 2 radio image, which I can't install because misc is fried.

So, in short, searching xda and the Internet in general hasn't helped much, except perhaps to better prepare me to follow somebody else's instructions :). In reality I have gone through several different sets of instructions multiple times and tried a variety of other things, but it always comes back to not being able to complete a radio image installation because of that problem with misc.

I'm willing to try just about anything... and I know there are quite a few others out there with a misc problem who can't seem to make any progress or get any input, so hopefully my exhaustive description of how I got here and what I've tried already will be useful to one of the local experts.